Bobbin thread replenishing mechanisms for sewing machine with oscillating shuttle

ABSTRACT

A LOCKSTITCH SEWING MACHINE HAVING AN OSCILLATING LOOP TAKER IS PROVIDED WITH A MECHANISM FOR REPLENISHING THREAD ON THE BOBBIN WHILE THE BOBBIN IS IN PLACE IN THE LOOP TAKER AND WHILE THE LOOP TAKER PARTAKES OF THE SAME OSCILLATORY MOVEMENT AS DURING STITCH FORMATION. MEANS ARE DISCLOSED FOR INTRODUCING THREAD TO THE BOBBIN IN PLACE ON THE LOOP TAKER, AND A RATCHET DEVICE IS DRIVEN BY THE OSCILLATING LOOP TAKER DRIVER FOR TURNING THE BOBBIN IN ONLY ONE DIRECTION TO WIND THE THREAD THEREON.

United States Patent Michael F.1vanko Rocltlway;

Stanley J. Ketterer, Morris Plains, NJ. 11,999

Feb. 17, 1970 June 28, 1971 The Singer Company New York, N.Y.

lnventors Appl. No. Filed Patented Assignee BOBBIN THREAD REPLENISHINGMECHANISMS FOR SEWING MACHINE WITH OSCILLATING SHUTTLE 6 Claims, 7Drawing Figs.

U.S.Cl 112/181, 1 12/186 Int. Cl D05b 57/14, D05b 59/00 FieldolSearch112/181,

[56] References Cited UNITED STATES PATENTS 3,012,530 12/1961 Kettereret al 1l2/186X 3.096.736 7/1963 Johnson. 112/181 3,386,400 6/1968 lvankol 12/186X Primary Examiner-H. Hampton Hunter Attorneys-Marshall J.Breen, Chester A. Williams, J r. and

Robert E. Smith ABSTRACT: A lockstitch sewing machine having anoscillating loop taker is provided with a mechanism for replenishingthread on the bobbin while the bobbin is in place in the loop taker andwhile the loop taker partakes of the same oscillatory movement as duringstitch formation. Means are disclosed for introducing thread to thebobbin in place on the loop taker, and a ratchet device is driven by theoscillating loop taker driver for turning the bobbin in only onedirection to wind the thread thereon.

PATENTEU JUNE 8 I97! SHEET 2 [IF 2 Fig. 6

INVENTORS. Mlchoel F. lvanko,

Stanley J. Ketterer BY// ATTOXE Y WITNESS:

75PM I /2M6 l BOBBIN THREAD REPLENISHING MECHANISMS FOR SEWING MACHINEWITH OSCILLATING SHUTTLE BACKGROUND OF THE INVENTION The technique ofwinding thread upon a bobbin in place in a rotary loop taker has beenquite highly developed, and as disclosed in the US; Pat. No. 3,012,530,to Stanley J. Ketterner et al. Dec. 12, I961 to which reference maybehad, the use of a rotating bobbin driving member in a rotary lop takerfor bobbin thread replenishment is well known. Where the bobbin drivingmemberand the loop taker drive each rotate, there need be no relativemovement therebetween during sewing operations and therefore,exceedingly simple, friction-free mechanismsare-possible. In anoscillating loop taker, however, prior known bobbin rotating devices,albeit theoretically plausible, would behighly impractical because ofthe complexity of construction and the bearing problems which wouldarise because of the relative motion which would exist during the longperiods of sewing while the bobbin replenishing means is ineffective.

Heretofore', bobbin thread has been replenished successfully on abobbin-in place in an oscillating shuttle by a process as disclosedin'the U.S. Pat. No. 3,096,736, to R. E. Johnson July 9, I963 in'whichat each needle reciprocation, a fresh loop of needle thread is seizedand cast onto the bobbin. In this patented construction bobbin threadreplenishment results from the successively deposited thread loopsrather than from a driven rotation of the bobbin.

BRIEF SUMMARY OF THIS INVENTION In the present invention, bobbin threadis replenished on a bobbin in place in an oscillating loop taker bymeans ofa ratchet drive for the bobbin by which the bobbin is rotated inincrements during thread replenishment by a driver which oscillates withthe loop taker driver. The same advantages of simplicity and absence offriction incident to relative motion of the bobbin and loop taker driverduring sewing is, therefore, attained with the present invention as hadheretofore been obtained with rotary loop takers. As compared with theprior known arrangement for replenishing bobbin thread in an oscillatoryloop taker in which successive loops are cast onto the bobbin, thepresent invention is advantageous in that the replenishment thread maybe directed through a bobbin thread tensioning spring and therefore, agreater uniformity of stitching can be obtained.

Another advantage of the construction of the present invention forreplenishing bobbin thread in an oscillating loop taker sewing machineis that a more even winding of thread on the bobbin can be attained andconsequently a greater quantityof thread can be replenished on thebobbin than an arrangement in which successive loops of thread aredeposited.

. DESCRIPTION OF THE DRAWINGS With the-above and additional objects andadvantages in view as will hereinafter appear, this invention comprisesthe devices, combinations, and arrangements of parts hereinafterdescribed'and illustrated in the accompanying drawings of a preferredembodiment in which:

FIG. 1 represents a vertical cross-sectional view of a portion of asewing machine work supporting bed showing an oscillating lockstitchforming loop taker together with a fragment of the oscillating drivetherefor in vertical cross section and having a bobbin threadreplenishing mechanism applied thereto in accordance with this inventionand shown in the retracted or sewing mode,

FIG. 2 represents an enlarged vertical cross-sectional view of thebobbin case of FIG. 1 with a fragment of the loop taker and a fragmentof the bobbin rotating member shown in effective positionfor influencingthe bobbin replenishing mode,

FIG. 3 is an exploded perspective view of the loop taker, bobbin casebobbin, and of the parts associated therewith for winding replenishmentthread on the bobbin,

FIG. 4 is a side elevational view of the bobbin case showing the needlethread being manually introduced thereto for initiation of bobbin threadreplenishment,

FIG. 5 is a front elevational view of the bobbin case together with anoscillating shuttle showing the needle thread manually introduced forinitiation of bobbin thread replenishment as in FIG. 4,

FIG 6 represents a cross-sectional view of the bobbin case takensubstantially along line 6-6 of FIG. 5 showing the relationship of themanually introduced needle thread to the bobbin flange upon initiationof bobbin thread replenishment, and

FIG. 7 represents a cross-sectional view taken substantially along line7-7 of FIG. 4 showing the disposition of thread during the course ofbobbin thread replenishment.

Referring to FIGS. 1, 2, 3, and 4 of the drawings, a work supporting bedof a sewing machine is indicated at 11 and is formed with a web 12apertured at 13 to accommodate a bushing 14. Journaled in the bushing isa loop taker drive shaft 15 which is formed with or has secured theretoa shuttle driver 16 at one side of the bushing 14. A collar 17 securedby a setscrew 18 to the shaft 15 at the opposite side of the bushinglocates the shaft axially in the machine bed.

Carried on the bed spanning a loop taker accommodating recess 20 thereinis a throat plate 2I formed with a needle aperture 22 and with slots 23through which extends a work transporting feed dog 24. Beneath thethroat plate and within the loop taker accommodating recess 20 isarranged a shuttle housing 25 which may be secured by any conventionalmeans to the web 12 in the bed and which is formed with a bearingraceway 26 in which a shuttle 27 is journaled. A housing cap 28 whichmay be hinged as at 29 to the shuttle housing is formed with a bearingprojection 30 complemental to the bearing raceway 26 in order toconstrain the shuttle within the housing. A bearing rib 31 on theshuttle which is constrained between the raceway 26 and the bearingprojection 30 is formed with a needle loop seizing beak 32 as isconventional and the shuttle is formed with a thread camming front skirt33.

The shuttle driver 16 engages with and moves the shuttle 27 in anoscillatory fashion alternately over somewhat greater than one-halfrevolution increments in opposite directions as is well known inoscillatory shuttle lockstitch sewing machines. The shuttle 27 is formedwith a central post 35 upon which is accommodated a bobbin case 36. Alatch device 37 on the bobbin case may be moved into and out of grippingrelation with an annular notch 38 formed on the extremity of the post 35to maintain the bobbin case in the shuttle and a rotation restrainingarm 39 on the bobbin case is embraced by a notch 40 formed in theshuttle housing cap 28 to prevent the bobbin case from oscillating withthe shuttle.

The bobbin case 36 is formed with a central sleeve 41 which embraces theshuttle post 35 and on which sleeve a hub 42 ofa thread carrying bobbin43 is freely rotatable. Preferably the bobbin is formed with identicalflanges 44. The bobbin case is also formed with a peripheral skirt 45which surrounds the bobbin 43. The skirt is formed with a thread guidingslot 46 into which thread from the bobbin may be led when the bobbinsare wound in conventional fashion while separated from the loop taker. Athread tensioning spring 47 secured to the skirt 45 as by a screw 48overlies the mouth of the thread guiding slot 46 and frictionallyopposes passage of thread from the bobbin.

The construction thus far described is conventional in the sewingmachine art and it will be understood that although a specific form ofconventional oscillating shuttle mechanism has been described, thisinvention as will now be described with relation thereto, may be appliedwith minor variation to any known oscillating lockstitch formingmechanisms,

Since in this invention, thread is to be wound on the bobbin in place inthe loop taker, provision is necessary for introducing thread from asource outside the shuttle to the bobbin. To this end an auxiliarythread guiding slot is formed in the bobbin case which, as shownparticularly in FIGS. 4, 5, and 6, extends from the face of the bobbincase to the skirt 45 and terminates at 61 closely adjacent to thetermination of the conventional thread guiding slot 46 so that thethread issuing from either slot 46 or 60 will be subjected to thetensioning effect of the spring 47. When the thread N from aconventional sewing needle, as shown in FIGS. 4, 5, and 6, is manuallyintroduced to the slot 60, this thread will be directed over the edge ofone of the bobbin flanges 44 as shown in FIG. 6.

Insofar as thread disposition is concerned, the needle thread N whenplaced and held as shown in FIGS. 4, 5, and 6, is in readiness to bewound on the bobbin. It is necessary that the thread guiding slot 60 belocated so that in regular sewing operations the threads will not bedirected into the slot 60.

The bobbin 43 in this invention is required to have two features whichdepart from conventional bobbin construction. First the periphery ofeach bobbin flange 44 must be formed with at least one radial slot 65.Although a single slot in each flange is sufficient, a plurality ofradial slots 65 in each flange will increase the speed at which threadreplenishment will begin. The slots 65 serve, when the thread isdirected over the flange periphery, as shown in FIG. 6, to catch thethread loop and anchor the thread to the bobbin when the bobbin isrotated. The second departure from conventional bobbin constructionrequired by this invention is a series of evenly spaced radial notches70 formed in the end face of each flange 44 of the bobbin.

It is the purpose of the radial notches 70 to provide for a ratchetdrive for the bobbin in one direction of rotation and to preventretrograde motion of the bobbin during bobbin thread replenishment.Cooperating with the radial notches 70 in one bobbin flange is a bobbindriving pawl 71 keyed and secured fast on a drive rod 72 by a screw 73.The drive rod is endwise slidable in an axial bore 74 formed in the looptaker drive shaft and a radial pin 75 set into the drive rod 72protrudes outwardly through a slot 76 formed lengthwise in the looptaker drive shaft. The bobbin driving pawl 71 may be retracted into acavity 77 formed in the shuttle driver 16 as shown in FIG. 1 or may beshifted out of'the cavity into engagement with the bobbin flange 44 asshown in FIG. 2 by means of a control lever 78 fulcrumed at 79 beneaththe bed 11. The control lever includes a handle 80 extending upwardlythrough an opening 81 in the bed for access by the machine operator. Thecontrol lever also is formed with a bifurcated extremity 82 each branchof which carries an inwardly extending pin 83 embraced by the annulargroove 84 in a collar 85 slidable on the loop taker drive shaft. A coilspring 86 arranged in the loop taker shaft bore 74 bears against thedrive rod 72 and biases the radial pin 75 towards the left as viewed inFIG. 1 against the collar 85. By manipulation of the handle 80,therefore, the pawl 71 may be shifted selectively into or out of drivingrelationship with the bobbin.

To prevent retrograde movement of the bobbin during the returnoscillation of the driving pawl 71, an annular spring member 90 isinserted in the bobbin case between the bobbin case and the bobbin.'Theannular spring member 90 is provided with a pair of curved spring arms91 and 92 which are bent laterally toward that side of the spring member90 which faces the bobbin, i.e., toward the right as viewed in FIGS. 1,2, and 3. The spring" arms 91 and 92 differ not only as to their radialposition but also in that the arm 91 is offset laterally to a greaterdegree. The spring arm 92 which is offset the least is disposed oppositethe ratchet notches 70 in the bobbin flange, the spring arm 91 is not inregistry with the notches 70. The spring member 90 is also formed with aperipheral tab 94 which is offset laterally in a direction opposite thespring arms 91 and 92 and which engages any one of a plurality ofapertures 93 formed through the face of the bobbin case to prevent thespring 90 from turning. The apertures 93 may be associated with thebobbin case latch 37 as is conventional in the type of bobbin casehereinbefore described or if a different type of latch device isemployed, apertures or recesses 93 may be formed in the bobbin case facefor anchoring the spring 90.

Only when the spring arm 91 is deflected by shift of the bobbin to theleft as viewed in FIG. 2 i.e., when the driving pawl 71 engages thebobbin to replenish thread, will the spring arm 92 engage the radialnotches 70 in the bobbin flange and thus prevent retrograde movement ofthe bobbin.

When the bobbin driving pawl 71 is retracted as shown in FIG. 1 so thatthe parts occupy a position for sewing, the spring arm 91 of the springmember 90 will shift the bobbin slightly to the right and the spring arm92 will become ineffective to prevent retrograde movement of the bobbin.The bobbin during sewing, therefore, will be free to turn and free topay out bobbin thread to the stitches being formed.

When the bobbin driving pawl 71 is shifted into driving engagement withthe bobbin as shown in FIG. 2, the spring arm 91 will be compressedlaterally so that'the retrograde preventing action of the spring arm 92will become effective.

In operation, therefor-e, thread may be replenished on the bobbin 43 inplace in the loop taker 27 when the operator of the sewing machineshifts the handle to the right as viewed in FIG. 1 to render effectivethe ratchet drive for the bobbin. In addition, the operator need onlygrasp a loop of needle thread as it is being manipulated by the shuttle27 and manually insert the needle thread into the slot 60 as describedabove. Subsequent operation of the sewing machine will thereafter causethe ratchet pawl 71 to drive the bobbin in increments in one directionof rotation. The needle thread being caught in one of the bobbin flangeslots 65 and thus anchored to the bobbin, will be wound onto the bobbinhub 42. The lead of the needle thread into the bobbin will immediatelybe drawn to the extremity 61 of the thread slot 60 in the bobbin caseskirt which as shown in FIGS. 1 and 2 is spaced centrally of the bobbinflanges 44. The resulting thread package wound on the bobbin willpresent an even distribution of thread on the hub 42 and the maximumlength of thread may thus be wound on the bobbin.

As illustrated in FIG. 3, the needle aperture 22 is located on theleft-hand side of shuttle bearing rib 31 so that the needle path throughthe aperture 22 will occur to the left of the thread engaging beak 32 ofthe shuttle. With this arrangement, with no work fabrics at thestitching point of the sewing machine the needle thread once manuallyinserted in the bobbin case slot 60 will no longer be presented to theshuttle beak 32 for loop seizure despite subsequent needle reciprocationduring bobbin thread replenishment. When replenishment of bobbin threadhas proceeded until a desired quantity has been wound on the bobbin, theoperator can terminate winding by shifting the control handle 80 to theleft as viewed in FIG. 1. When work fabrics are then placed at thestitching point of the sewing machine and the sewing machine needle isnext lowered to penetrate the work fabrics, a needle thread loop will bepresented to the shuttle beak 32 and this loop will be concatenated in aconventional fashion about the bobbin in the shuttle to form alockstitch with the thread previously wound on the bobbin.

Having set forth the nature of this invention, what is claimed hereinis:

We claim:

1. In a lockstitch sewing machine having an endwise reciprocatory threadcarrying needle, an oscillatory loop taker having a thread-carryingbobbin journaled therein, and an oscillating drive member for impartingmovement to said loop taker for cooperation with said needle in theformation of lock stitches, mechanism for replenishing thread from saidthreadcarrying needle onto said bobbin in place in said loop takercomprising a bobbin driver carried for oscillation with said loop takerdrive member, overrunning clutch means carried on said thread carryingbobbin and on said bobbin driver for drivingly coupling said bobbin withsaid bobbin driver in only one direction of oscillation of said bobbindriver, and means for selectively shifting said overrunning clutch meansinto and out of cooperative interrelation.

2. A bobbin thread replenishing mechanism for a sewing machine as setforth in claim 1, in which said overrunning clutch means comprises afirst ratchet and pawl arrangement including a ratchet means formed onsaid bobbin and a spring loaded pawl carried by said oscillating drivemember-and arranged for cooperation with said ratchet means 3. A bobbinthread replenishing mechanism for a sewing machine as set forth in'claiml in which said thread-carrying bobbin is journaled in a bobbin casewhich bobbin case is restrained from partaking of the oscillatorymovement of the loop taker, and in which a retrograde overrunning clutchmeans is carried onsaid thread-carrying bobbin and on said bobbin case.

4. A bobbin thread replenishing mechanism for a sewing machine as setforthvin claim 2 in which said thread-carrying bobbin is journaled inl abobbin case which bobbin case is restrained from partaking of theoscillatory movement of the loop taker, and in which a second ratchetand pawl means is provided on said bobbin and said bobbin case forpreventing retrograde movement of said bobbin during the other directionof oscillation of said bobbin driver.

5. A bobbin thread-replenishing mechanism as set forth in claim 4 inwhich said f rst and second ratchet means are both carried on saidbobbin and each ratchet means takes the form of similarly spaced seriesradial'notches formed on a respective one of the bobbin flanges.

6. A bobbin thread-replenishing mechanism as set forth in claim 5 inwhich said second pawl means comprises an annular spring member adaptedto be positioned between said bobbin case and said bobbin, said annularspring member including at least one spring arm laterally offset towardsaid bobbin case

